ON THE FUNCTIONS OF THE CEREBRAL CORTEX. 
37 
and the animal being to all appearance well on the third day), but was not followed 
by recovery, death being the result of shock. 
The left side of the brain of this Monkey is represented as seen from below in 
fig. 29, Plate 4. 
30. 
Lesion. — Ablation of right temporo-sphenoidal lobe and hippocampus major. 
.The lesion involves only the middle of the hippocampal gyrus. 
Result. — As regards sensibility, we could detect no difference on the two sides. 
As regards hearing, when the ear on the same side as the lesion is stopped the 
animal seems unable to hear slight sounds. 
No other result was obtained. The animal was kept seven weeks. 
The lesion is shown in fig. 30a (Plate 5) as seen from the outer aspect, and the 
extent to which the hippocampal gyrus is involved is exhibited in fig. 30b. 
31. 
Lesion. — In this animal the greater part of both temporo-sphenoidal lobes was 
removed in four successive operations, with an interval of rather more than a month 
between the first and second, about twelve days between the second and third, and a 
little more than a month between the third and fourth. The first two operations 
involved all but the superior gyri, but the hippocampal convolution was not reached 
by the lesion except at its middle part on the right side, where at one point only 
the injury extended quite to the edge of the hemisphere. Upon the left side the 
apex of the lobe was left intact, but on the right side it was almost entirely 
destroyed. In the third operation both the superior temporo-sphenoidal gyri were 
cut away ; but on the right side the superior extremity of the gyrus for about three- 
eighths of an inch also remained intact, and on the left side the lower extremity. 
In the fourth operation the hippocampus on the right side, which had not been 
reached at the first operation, was exposed and excised along a considerable extent. 
Result. — The extensive lesions in the brain of this Monkey produced no discover- 
able symptoms, with the exception of a temporary diminution of sensibility, lasting 
about a week, or rather more, upon the left side, following the operation for removal 
of the right hippocampus major. There was no motor paralysis, no diminution of 
sensibility, even for tactile impressions, and hearing was to all appearance quite acute 
even the day after the destructiou of both temporo-sphenoidal gyri (the remainder of 
the temporo-sphenoidal lobes having, as we have seen, been previously removed). 
This animal was kept alive for nearly five months after the first operation. 
The brain is represented in figs. 31a, b, c, and d. 
32. 
Lesion. — Ablation of the greater part of the right temporo-sphenoidal lobe (a small 
(postero-superior) part only of the superior gyi"us, the posterior extremity of the 
